Collapsible and expansible vessel.



W. M. FULTON.

GOLLAPSIBLE AND EXPANSIBLE VESSEL.

APPLIOA'I I ON I'ILED JULY 19, 1904.

Patented Nov.15

M I Inventor Q r MW,

WESTON M. rUL'roN, or KNoxvrLLu-rENNEssEE, AssmNoE TO THE rUL'roN com- PANY, E KNOXVILLE, TENNESSEE, A conronatrroN 0E MAINE.

COLLAISIBLE AND EXPANSIBLE VESSEL.

Patented Nov. 15, 1910.

To all whom it may concern:

Be it known that I, WEs'roN M. FULTON, of

Knoxville, Tennessee, have invented a new and useful Improvement in Collapsible and Expansible Vessels, which invention is fully set forth in the following specification.

sheet steel having electrically welded seams are flexible and quite durable under certain conditions of use, but it is desirable at times to have the flexible wall of a collapsible and expansible vessel made of metals not readil d best 0 vessels.

welded such as copper and brass, and WlllC resist the oxidizin action of air and moisture. Such vesse are especially useful when the same are to be employed, for example, as the expansible and contractible portion of a steam gage, or as the thermosensitive portion of devices for gaging the temperatures of liquids. In devices of this character, steel readily corrodes and is not serviceable even when protected by metal coatings of tin, zinc or nickel, because the such coatings are porous and crack in use, exposing the iron to oxidation and rusting. For these reasons it is desirable to use in vessels of this kind a metal or alloy that will not readily corrode, such as cop er or brass. In making the walls of colla si le vessels out of sheet copper or sheet rass, a seam is necessarily formed, and it has been found that the seams rapidly give Way to the bending strains and break; therefore, seamless wrought tubing is referable for constructing such vessels. have found that even seamless wrought tubing is liable to develop weakness at the bends in the corrugations, thus unfitting it for use in constructing the walls of corrugated collapsible In most of the methods practiced in the manufacture of seamless tubing, there is formed a hard surface (both the interior and exterior surface of the tube) of greater density than the intermediate portion of the seamless tube, such as a tube, that is, the portion lying between the exterior and interlor surfaces thereof. Thus, for example, when a tube is drawn between a mandrel and a die, the operation results in condensing and hardening the surface portions of the metal wall, leaving the interior or intermediate portion of. the wall more or less unaffected in these respects. The dense surface layers possess quite a different molecular structure from the intermediate layer or portion in their physical qualities, such as hardness, brittleness, expansion and contraction under the influence of heat and also in elasticity. In the case of brass tubing made in this way, and particularly when the metal of the tubing is of any considerable or appreciable thickness, the coeflicierit of expansion of the dense surface layers (whether of the interior or the exterior surface) differs so widely from that of the intermediate layer that the ordinary changes in atmospheric temperatures cause the tube to crack. Although annealintg reduces to anappreciable-degree this di ference in molecular structure between the intermediate and surface layers, and prevents cracking for ordinary purposes, yet such annealing fails to render, the drawn tubing serviceable for making thewalls of flexible corrugated collapsible vessels which are to withstand repeated expansion and contraction. The same is true of other kinds of wrought seamless met-a1 tubing, such as rolled tubes. When such wrought tubings are employed as the walls of corrugated expansible and contractible vessels, the greatest strains, and therefore the cracking, makes its appearance immediately at or adjacent to the point where the bend occurs, and where, consequently, the greatest stress is set up.

The object of the present invention 1s to provide Walls for such ex ansible and contractible vessels, which shall be seamless, and free from a liability to crack even under the conditions imposed by long use and severe, strains due to great internal pressures, and which preferably also shall be free from oxidation and the cracking resulting from such oxidation.

With this object in view, the invention consists in the expansible and oontractible walls of a vessel formed from a wrought drawn or rolled rugated; and

layer shall be of substantially uniform den-- sity, hardness, brittleness and elasticity. For example, by removing the exterior surface or portion and. the interiorsurface or portion of the tube, leaving only the intermediate or middle portion of the tube, that is,\-the portion lying between the exterior surface portion and the interior surface portion thereof, and then "corrugating this intermediate ortio'n of the tube, so as to form the walls 0 the ex ansible and contractible vessel, the said wal s will not only be seamless, but the metal at the point of bend (and in this case throughout the entire bod of the-wall) will be of substantially uni orm molecular structure, and of uniform hardness, brittleness and elasticity throughout the thickness of the wall.

The inventive idea involved is capable of being embodied in a variet of forms, one of which, for the purpose 0 illustrating the invention, is shown in the accompanying drawings, in which .Figure 1 shows a wrought tube, either drawn or rolled from a cast ingot in the usual way; Fi 2 is a You 'tudinal section of the same; F1 3 is the tu e of Fi 1 corig. 4 shows the tu on a mandrel for the purpose ofremoving the exterior surface ortion thereof.

Referring to t e drawings, 1 indicates a wrought metal seamless tube, as a die-drawn tube of metal, such as brass, for example, the

thickness of the tube being hi hly magnified for the sake of illustrating the molecular condition of the wall. portion of the tube is indicated by 3, and the outer surface portion thereof by 4.

These portions have been compressed and hardened in the act of forming the tube, as by contact with the mandrel and the die respectively, in the case of a drawn tube. The'intermediate ortion of the tube is indicated by 5. T 's portion has been removed from, and has not been subjected to,

the compressing action experienced by the surface portions of the tube durin the manensit of ing. It will beseen that the wall of the wrought tube, as of a die-drawn tube, is not of homogeneous structure in passing The inner surface through the wallfrom one side to the other thereof, but is composed of layers more or section, a sin 1e corrugation is shown be-- tween the lea -lines from'the reference numeral 6. If the wallof this vessel is collapsed, the outer la er 4 of saidwall will be compressed, whi e the layer 3 will be drawn out or put under tension. The middle-layer 5, which is relatively neutral, will serve to intensify the strain on layers 3 and 4, by virtue of the fact that it separates them from each other. When the wall is expanded, the reverse action takes place. These repeated strains actin upon these severallayers of different mo ecular structure alternately and in opposite directions, cause an ultimate separation of the layers and cracks in the surface layers 3 and 4, which, when once formed in the surface rapidly extend through the-wall and render it useless.

For the purpose of obviating the difiiculties resulting from the different molecular structure of the several layers 3, 4 and 5, I remove one, and preferably two, of the non homogeneous layers composing the sheet of metal, at and adjacent to the point or portion of the wall where the bend of the corrugation occurs. The most convenient, and

this result is to remove one, and preferably .two, of said la ers throughout the entire extent of the b y of the wall. These layers may be removed in any convenient or eflicient manner, the particular way of accomplishing this removal not being material to the present invention, it only being essential that such layer or, layers be removed without materially tion of t e remaining layer or layers. To illustrate one method of accom lishing this removal, a wrought seamless tu e is formed, lpfleferably 'of brass, by any of the wellown methods for forming such tubes,-such as drawing from a cast ingot. This tube then has its outer surface la er 4 removed in any suitable way, as by a mandrel 7, as shown in i 4, and the surface layer 4 turned off. T e inner surface layer 3 may then be removed in any suitable manner, as by turning or borin leaving the intermediate portion 5, whic is then dee 1y corrugated, as indicated in Fig. 3, and there results a flexible elastic corrugated wall of substantially uniform molecular construction, which wall may be affecting the molecular oonstrucacing it upon elongated and compressed, and which will withstand repeated strains without danger of cracking.

Although I prefer to remove two of the layers as indicated in the above example, yet in some cases only one may be removed, and the advantages of the invention to a certain degree will still be retained. I have found, however, that by removing from 50 to 80% of the entire wall, the best results are obtained, and I preferably employ seamless drawn tubing, though in some instances, seamless brazed tubing may be used, if desired.

By the term wrought seamless tubes, as used herein, I mean seamless tubes which have been formed by any method of treating t-he'metal thereof which gives to the surface or surfaces of the tube a different molecular structure, resulting in greater density, brittleness, hardness and variation in coefficient of expansion than the intermediate portion of the metal constituting the wall of the tube. Examples of such tubes are the ordinary die-drawn and rolled tubes familiar in the art.

What is claimed is y 1. A wall for an expansible and collapsible vessel consisting of a corrugated wrought metal tube having one of the surface portions of the wrought tube removed opposite the bends in the corrugations.

2. A wall for an expansible and collapsi-. ble vessel consisting of a corrugated seamless ing witnesses.

wrought metal tube having the interior and exterior surface portions of the wrought tube removed opposite the bends in the corrugat-ions.

3. A wall for an expansible and collapsible vessel consisting of a corrugated drawn metal tube having one of the surface portions of the drawn tube removed opposite the bends in the corrugations.

4. A wall for an expansible and collapsible vessel consisting of a corrugated drawn metal tube having the interior and exterior surface portions of the drawn tube removed opposite the bends in the corrugations.

5. A wall for an expansible and collapsible vessel consisting of a corrugated seamless wrought metal tube having one of its surface portions removed.

6. A wall for an ex ansible and collapsible vessel consisting o the corrugated intermediate portion of a seamless wrought metal tu e.

7. A wall for an expansible and collapsible vessel consisting of the corrugated intermediate portion of a seamless drawn metal tube.

In testimony whereof I have signed this specification in the presence of two subscrib- WESTON M. FULTON.

Witnesses:

Jon B.. SAMUEL, J. F. VOORHEES. 

